Science Daily October 25, 2022
Cubic boron arsenide (BAs) is promising for microelectronics thermal management because of its high thermal conductivity. Recently, its potential as an optoelectronic material was explored. However, it remains challenging to measure its photocarrier transport properties because of small sizes of available high-quality crystals. A team of researchers in the US (UC Santa Barbara, University of Houston) used scanning ultrafast electron microscopy (SUEM) to directly visualize the diffusion of photocarriers in BAs single crystals. They observed ambipolar diffusion at low optical fluence with persistent hot carrier dynamics for above 200 ps, which could likely be attributed to the large frequency gap between acoustic and optical phonons, the same feature that is responsible for the high thermal conductivity. At higher optical fluence, they observed spontaneous electron-hole separation. Their results show BAs is an attractive optoelectronic material combining high thermal conductivity and excellent photocarrier transport properties. According to the researchers their work demonstrates the capability of SUEM to probe photocarrier transport in emerging materials…read more. TECHNICAL ARTICLE
Credit: Matter, October 18, 2022Â